Abstract

Focal Cortical Dysplasia (FCD) is characterised by abnormalities in cortical lamination, myelination, cell types and sizes in addition to white matter abnormalities. These tissue characteristics of interest lend themselves to investigation with diffusion MRI, that attempts to access differences in water mobility within the tissue environment. Initially studies, and a substantial amount of subsequent research, has aimed to use measures based on metrics from diffusion tensor models such as Fractional Anisotropy (FA) and Mean Diffusivity (MD). These measures were sensitive, particularly to visible tissue abnormalities but lacked specificity and have not been useful for epilepsy surgery. However, they have illustrated that changes are occurring in widespread networks beyond the epileptic focus. Recent advances in hardware and pulse sequence design have made the acquisition of multi-shell diffusion data feasible in clinical scan-times. This data can be analysed using more advanced models such as NODDI[1] and the SMT[2] that aim to separate diffusion contributions from the orientational structure of the tissue. This allows for more specific changes related to microstructural parameters to be measured that could be more specific, helping to find focal abnormalities. There is currently increased interest in utilizing diffusion MRI to understand and characterise diffusion properties in gray matter [3] to measure cortical architecture. Significant challenges remain to obtain data with sufficient resolution in-vivo. However, in the future, gray matter diffusion in FCD affords a unique opportunity both to detect subtle pathological cortical abnormalities and offer the potential for validation of in-vivo imaging data owing to tissue availability following epilepsy surgery.

Acknowledgements

No acknowledgement found.